The columnar to equiaxed transition of CoCrNi medium-entropy alloy fabricated by laser directed energy deposition

• DOI: 10.1016/j.matdes.2023.112538
• Publication Date: 2023-12-04T11:33:25Z
• Authors: Wenjie Zhao; Yonggang Sun; Pengcheng Che; Zhiliang Ning; Hongbo Fan; Haiyan Yang; Jianfei Sun; Peter K. Liaw; Alfonso H.W. Ngan; Yongjiang Huang
• Keywords: Equiaxed crystals; Supercooling; Recalescence

Understanding and revealing the evolution mechanism of columnar to equiaxed transition (CET) that occurred in laser direct energy deposition (LDED) fabricated medium-entropy alloys (MEAs) is crucial for achieving tunable microstructure mechanical properties. In present work, a CET map was established explain effect density (LED) on LDED single tracks CrCoNi MEA. The results show observed related morphological transformation cellular substructure, which governed by constitutional undercooling. With increase LED, maximum value undercooling exceeds critical nucleation earlier, facilitates heterogeneous inhibits epitaxial growth rod-like cells, finally causes promoted CET. correlation among average cell size, geometrically necessary dislocation density, hardness also discussed. work not only uncovers grain LDED-fabricated MEA but provides theoretical guidance fabricating other MEAs with ideal performance.